The present invention relates to a semiconductor device and a manufacturing method thereof, which can be used for, e.g., the manufacturing of a semiconductor device including a higher-breakdown-voltage transistor.
A semiconductor chip has an I/O (Input Output) region including a circuit which performs input/output operations with a device outside the semiconductor chip, a power supply circuit, or the like. In the I/O region, a higher-breakdown-voltage MISFET (Metal Insulator Semiconductor Field Effect Transistor or MIS type field effect transistor) which is driven with a voltage higher than that for driving the MISFET formed in a logic region (core region) is provided. The higher-breakdown-voltage MISFET may be used to supply a high voltage to a nonvolatile storage element.
Patent Document 1 (Japanese Translation of PCT Application No. 2005-533370) describes a memory transistor including a structure in which a gate electrode is formed over a floating gate electrode via an ONO (Oxide Nitride Oxide) film.
Patent Document 2 (Japanese Unexamined Patent Application Publication No. 2014-103204) describes a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) including a gate electrode formed of a multi-layer film including polysilicon films in two layers.